1. Field of the Invention
The present invention relates to a machine for unloading hams and the like from the moulds. More particularly, the present invention relates to a machine that performs in a fully automatic way all operations that are required for removing hams and the like from the moulds in which such products are usually cooked.
2. Description of the Related Art
As is well known to those who are skilled in the art, hams and all other similar meat products are cooked within suitable moulds which are similar to pots or kettles provided with a pressure-tight lid. In such containers, whose general structure is actually standardized, the lid is of such size as to fit freely between the vertical walls of the mould, so that the lid itself rests directly on the product contained in the mould and presses the product by means of the pressure-hooking system.
Said hooking system consists of a horizontal crosspiece assembled above the lid, and bearing at its two ends two hinged arms having a rack-shaped profile facing the mould. The crosspiece is assembled on two fixed pillars on said lid and it is kept spaced from the lid itself by two helical springs inserted around said pillars; the rack-arms, at the very moment of closing, hook on the projecting rim of the mould with their teeth, and the closure is strongly secured by the two return helical springs which push said crosspiece upwards, thus forcing the two rack-arms into interference with the rim of the mould.
Though all moulds have the structure mentioned above, they are quite different by shape and sizes according to the meat product that is processed in the same: such moulds can be globally of a parallel-epipedal shape, or they can be roundish in various ways, and cross-piece of the lid in some versions can be provided with a shorter arm at right angles so as to form a Latin cross.
Although shapes and sizes are variable, being the hooking system of the lid unified, the operations required for removing the product from mould after cooking are in practice always the same: they consist in unhooking the racks from the projecting rim of the mould, which operation is made easier by exerting a pressure against the springs on said crosspiece, in removing said lid, and finally in unloading the product from the open container. This last operation is generally made difficult by the fact that the product adheres to the walls of the mould, so tha tit can be necessary to strike and shake the mould while in the upside down position; sometimes it is preferable to have recourse to the introduction of compressed air through a hole which is usually provided in the bottom of the mould.
The mould unloading operation of hams and the like is carried out at the present time generally by hand, and it is very laborious and even dangerous. In all cases such operation needs quite a large amount of manpower in order to keep the working times on the same levels of the other productive steps. Owing to the high resistance exerted by the return springs, those who are in charge of that operation have to make use of a hammer or the like for striking the cross-piece in order to cause the racks to release themselves and then, once the lid is removed, they have to unload energetically the ham from the mould.
Various automatic methods have been suggested in the past for carrying out the mould unloading operation of hams and the like by means of machines suitably designed, so as to avoid or reduce the difficulties in connection with the manual operations.
For instance, the machines disclosed in the French patents Nos. 1,255,857; 1,334,429 and 2,387,609 are capable of removing the product from the moulds when they are already free from their lids and in the upside down position, whereas the preceding operations of removing the lids and of turning the moulds upside down are kept manual: this one appears to be just a partial solution to the problem in question.
The machine disclosed in the French Pat. No. 2,553,333, on the contrary, carries out automatically all the necessary operations starting from the closed mould, up to the evacuation of the products and of the empty containers. However, it is to be remarked that the removal of the ham from the open mould is not carried out by the action of gravity, through turning the open mould upside down, but it is obtained through a procedure which is surely less valid, which consists in lifting the ham out of the open mould by clamping it by means of a sucker provided with air suction.. This type of gripping being very weak, also taking into consideration the remarkable weight of the product to be lifted, it is impossible not to remark that such system is strongly unreliable.
Another patent regarding that subject, i.e., the Italian Pat. No. 1,128,810, teaches a machine for mould unloading of hams and the like which carries out sequentially the operations of: unhooking and removing the lid, turning the mould upside down, removing the product by extracting the same from the mould by the action of gravity and with the help of insufflation of compressed air through the above-mentioned hole in the bottom of the mould, and evacuating the unloaded product from the mould as well as the empty containers; Such machine performs a working cycle of a discontinuous type, as it subjects to the operations just one mould at a time, on which mould the machine performs sequentially the operations mentioned above. The further mould to be subjected to such process can only be accepted after the preceding empty container has been evacuated. Such feature, which makes the machine's productivity unacceptably low, derives from the structure of the apparatus itself: the fundamental element on which the machine's design is based is a "container", substantially in the shape of a U. the mould to be opened is housed and locked in said container, which is rotatable about a horizontal axis between an upright position in which the mould placed in it is deprived of its lid, and an upside down position in which the product drops out of the open mould onto an underlying conveyor. Said container is provided with a removable "adaptation block", that can be changed so as to fit with the particular kind of mould undergoing the process.
It is to be remarked that, once the product is unloaded from the mould, the empty mould goes back to the upright position together with the "container" of the machine, then it is discharged, and only at that moment another mould to be opened can be fed.
In order to obviate the drawback of the excessive slowness of the working rhythm, a variant is suggested by the same patent mentioned above consisting in a double "container", which is capable of accepting a mould in the upright position and simultanously another one in the upside down position, two such moulds being opposite to one another with respect to the rotation axis of said "container". Such solution results in doubling the productivity with respect to the preceding design, but the structure of the machine, as well as the structure of the relative control diagram, which are already very complex, become further complicated.
In addition to the drawbacks already mentioned above, all the solutions disclosed have the drawback of being hardly adaptable to moulds of different shapes and sizes: for instance, in the case of the last machine disclosed above, if the type of the products to be processed is changed, the so-called "adaptation block" is to be changed. Sometimes the mechanical members for unhooking the lid are also to be changed, as the length of the crosspiece, and hence the distance between the two rack-arms, can change from a given mould type to another one.